04/28/2026
A new study published in ESMO Open (Sasagawa H et al., PMID: 41950573) explored whether BRCA mutations may be associated with less common cancer types. This was a Japanese case-control study that included nearly 3,500 patients with nine less common cancers (bladder, bone, brain, head and neck, sarcoma, skin, te**is, thyroid, and ureteral cancers) and nearly 39,000 control patients without cancer.
🔸 This is a case-control study, meaning the researchers compared how often BRCA1/2 mutations were found in people with these cancers versus those without, and used an odds ratio (OR) to estimate risk. An OR of 1.0 means no difference. An OR of 5.0 means the mutation is about five times more common in one group compared to the other.
⭐️ What did they find?
There were four significant associations:
1️⃣ BRCA1 with thyroid cancer (OR 5.25)
2️⃣ BRCA2 with bladder cancer (OR 4.67)
3️⃣ BRCA2 with head and neck cancer (OR 3.89)
4️⃣. BRCA2 with skin cancer (OR 6.13). For bladder cancer, the association stronger in females than in males.
🔸Let’s break this down:
-58 out of 38,288 individuals in the control group had a BRCA1 mutation (0.15%)
-5 out of 734 patients with thyroid cancer had a BRCA1 mutation (0.68%)
-This translates to an odds ratio of 5.25—meaning BRCA1 mutations were about five times more common in individuals with thyroid cancer compared to those without cancer.
⭐️ But here’s the key point: Although the relative risk sounds high, the absolute risk remains very low.
Think of this as increasing your chance of a rare event—like being upgraded on a flight ✈️. Your odds might be several times higher, but it still doesn’t happen very often.
My takeaways:
-Interesting association but not proof of causation- we need more research
-If diagnosed with one of these cancers, consider genetic testing.
-If you have a BRCA mutation, talk w your team re role of screening (no guidelines yet)
-could PARP inhibitors play a role in the future?
